1. Field of the invention
The present invention relates to an indication display unit for a vehicle, which employs so-called a head-up display, the arrangement being such that an image indicated on an indicator is reflected by a reflecting member disposed in front of a windshield, whereby its virtual image is visibly observed being overlapped with an outside scenery viewed through the windshield thereof.
2. Description of the Prior Art
It has heretofore been proposed to adopt the head-up display, taking account of ensuring more space in compliance with the requirement for diversification of the indicators, and of better visual observation of indicated images during the driving.
Turning first to FIG. 12, there is illustrated an example of a conventional indication display unit for a vehicle adopting the above-mentioned head-up display.
In FIG. 12, a projector generally designated at 11 is secured to a ceiling 10 in the car room for indicating various vehicle driving operational information such as a vehicle speed and so on. The reference numeral 12 represents a semi-translucent mirror provided upwardly from a dashboard 30 disposed in front of a windshield 20. An image 13 indicated on the projector 11 is projected to the semi-translucent mirror 12 to be reflected thereon in such a way that the image 13 can be visibly observed from the driver seat as a virtual image overlapped with an outside scenery viewed through the windshield 20.
With this arrangement, the driver is allowed to visibly recognize the vehicle operational information such as engine-speed, residual fuel quantity and so on without averting his visual field to a great extent during the traveling.
If the head-up display is adapted to display warnings such as a half-closed door, shortage in oil and so forth, the driver can immediately recognize occurrence of abnormal conditions during the traveling.
There are, however, some problems inherent in the prior art display unit. More particularly, the indicated image is reflected by a single piece of reflecting surface as observed in the case of the semi-translucent mirror 12, and hence in order to obtain a large amount of indications to be observed, a good deal of information has to be indicated on the same projector, and thus a large-sized projector is required, resulting in a problem in terms of space for installation.